ES2253730T3 - SWITCH FOR AN ELECTRIC MACHINE. - Google Patents

Abstract

A commutator for an electric machine comprises a support member ( 1 ) made from an insulating molding compound, a plurality of metal conductor segments ( 3 ) disposed thereon in evenly spaced manner around the commutator axis ( 2 ), with terminal elements disposed thereon for a rotor winding, and an interference-suppression device ( 9, 9 '), to which the conductor segments ( 3 ) are connected in electrically conductive manner and which comprises a number of individual interference-suppression elements ( 10 ) corresponding to the number of conductor segments ( 3 ), wherein the conductor segments ( 3 ) are provided with contact tabs ( 18 ), which are respectively connected, at a distance from their root points ( 19 ), via associated contact points ( 23 ), to the adjoining contact poles ( 24 ) of two neighboring interference-suppression elements ( 10 ). These contact tabs ( 18 ) are designed to be radially resilient and, in the region between their root point ( 19 ) and their contact point ( 23 ), are separated from the adjacent rigid components of the commutator in such a way that, in this region, the position of the contact tabs ( 18 ) relative to that of these respective rigid adjacent components of the commutator can vary as a function of thermal expansion.

Description

Switch for an electric machine.

The present invention relates to a switch for an electric machine, comprising a support body manufactured from insulating molding material, a multitude of metal conductive segments arranged in it regularly around the axis of the switch with connection elements arranged for a rotor coil and an antiparasitic mechanism,  with which they are connected in a conductive way of electricity the conductive segments, and comprising a number of elements individual antiparasitic agents corresponding to the number of conductive segments, in which the conductive segments they have contact tabs, which are attached respectively away from their base points in contact points assigned with the bordering poles of two antiparasitic elements contiguous

Switches of different modes of Construction (drum switches, piano switches) are They know in multiple configurations. The switches increase, especially in the case of its realization as a switch of drum, equipped with spark suppression mechanisms, for avoid damaging the electronic assembly groups arranged in a way spatially close to the respective electric machine by the formation of sparks in the commutator.

These antiparasitic mechanisms were distributed  so far made as antiparasitic discs so annular that are composed of a material with a resistance dependent on the voltage, which are conductively attached to electricity with conductive segments. The disc corresponding antiparasitic may also be arranged on the one hand, radially outside the tread surface of the brush (see, for example, documents US 5895990 A, US 5717270 A, GB 2183933 A and US 5796203 A) or, on the other hand, radially inside the rolling surface of the brush (see, for example, documents UJ 6285106 B1 and DE 19953231 A1). Also, special forms of switches are known. antiparasitic drum, in which the conductive segments are arranged outside in cylindrical antiparasitic sleeves (see DE2055648 and DE3614869 C2). EP364292B1 describes a drum switch with a support body that is composed of thermoplastic material, in which it is planned radially below the bonding tails a reinforcement ring resistant to heat, which may have an antiparasitic coating or be arranged adjacent to a separate antiparasitic ring; also, the reinforcement ring is also arranged as the separate antiparasitic ring, if necessary, provided complementary in a support body seat, where it is fastened by the tabs protruding from the conductive segments.

Regardless of the specific provision respective of the antiparasitic disk, in all the switches totals whose antiparasitic mechanism comprises a disk Annular antiparasitic, costs are disadvantageous considerable for the antiparasitic mechanism. Since the material ceramic, from which the disks are normally manufactured Antiparasitic of this type is very expensive, and in the manufacture of antiparasitic discs, in which these are trimmed from a plate Multilayer ceramic-metal, are wasted large quantities.

In general, of drum switches known antiparasites that use an antiparasitic disk, to many practical applications come into consideration only compact drum switches with antiparasitic discs arranged radially within the race surface of the brush, due to the limited space available for the respective switch. Another problem of drum switches of this type with radially arranged antiparasitic rings inside the rolling surface of the brush results from thermal expansion behavior other than disk antiparasitic that is usually composed of ceramic material compared to the remaining components of the switches respective. The corresponding thermal stresses, while not take special measures, can lead to premature breakdown of the switches as a result of broken antiparasitic discs and / or destroyed junctions of the conductor segments with the disks antiparasitic To solve this problem, in the DE document 19953231 A1 is proposed to join the antiparasitic disk with a Elastic adhesive with the support body and connect the segments conductors to the antiparasitic disk through thin wires, which on the one hand they are welded to the tail of the conductor segment assigned and, on the other hand, to a disk metallization zone assigned antiparasitic. According to US 6285106 B1, which gives a drum switch of the generic type is known, are provided sheet springs opposite to the electrical contact of the conductive segments with the antiparasitic disk, which are arranged within a hollow annular space, which is bounded by the support body, the conductive segments and a annular cover and in which the disk is also housed antiparasitic The sheet springs, which allow a radial thermal damping other than the antiparasitic disk, on the one hand, and the other switch mounting parts, by on the other hand, they may be attached, especially, to the cover of ring shape

In the known drum switches rated  previously with a radially arranged antiparasitic disk within the conductive segments it is especially disadvantageous the high manufacturing cost that opposes the competitive ability of drum switches corresponding that, especially in the case of the switch according to EP364292B1 in addition to the high costs of manufacturing for the antiparasitic disk (see above,) is based mainly on the high number of mounting parts that They must be assembled. On the drum switch according to the document EP 364292 B1 is disadvantageous that the resulting contact only in the support force of the sheet springs with the segments of driver and with the antiparasitic disk is not reliably reliable durable and, for example, can be damaged by corrosion.

Document DE 433845 A1 discloses a switch made as a drum switch of the generic type with an antiparasitic mechanism, comprising elements Individual antiparasitics introduced into the support body. Each conductive segment is connected, at the same time, by two fastening loops inserted in the support body that they serve to ensure the position of the driver segment respective. In this switch, high costs do not appear such as those linked to the case of the switches explained previously with the availability of the antiparasitic disk of ring shape However, due to dilatation behavior different thermal explained previously from the different materials, of the switch according to DE 4338345 A1 only a limited service life of the contact of the conductive segments with antiparasitic elements.

The objective of the present invention is based on facilitate, in the light of the state of the art explained formerly, a long-life, reliable and anti-parasite switch of the generic type, which can be manufactured with a small cost of low cost manufacturing, where it should be possible especially preferably, manufacture a switch antiparasitic with basically equal dimensions as in the case of a non-deworming switch of the same design.

This objective is achieved according to the present invention so that in the case of a switch of the type generic, the contact tabs are made in a way elastic and in the area between its base point and its contact point are separated from the adjacent mounting elements fixed, so that in this area the relative position of the contact tabs may vary conditioned by dilation thermal with respect to these fixed mounting parts adjacent to these of the switch.

A first characteristic property of switch according to the present invention is that the mechanism antiparasitic does not include an antiparasitic disk so annul, but a number of individual antiparasitic elements corresponding to the number of conductive segments; those elements  individual antiparasitic as multilayer capacitors they can present, especially, a square shape, they can manufactured from a metal-ceramic plate multilayer without clipping and, thus, especially economical. Furthermore, it is characteristic for the switch according to the invention that the contact tabs, which are manufactured as a component integral of the conductive segments, that is, in one piece with the other zones of the conductive segments, serve for direct contact of the conductive segments with the elements antiparasitic; thus, the switch according to the present invention does not have additional mounting parts, as expected according to the state of the art, especially in the form of wires and sheet springs for the contact of the switch elements With an antiparasitic disk. As "union" of the tabs of contact with the contact poles of the two elements contiguous antiparasitic a conductive contact must be understood Of electricity; especially, a separate bonding material, such as welding. He direct and immediate contact of the contact tabs formed of a single piece in the conductive segments with the antiparasitic elements, without this having effects disadvantageous over the life of the switch, it is possible to so that the contact tabs can be deformed to compensate the thermal expansion behavior other than the pieces of Individual switch assembly. The deformability of the contact tabs are obtained, on the one hand, from their elastic realization, being the contact points, in which the contact tabs with the elements are attached antiparasitic, separated from the base points of the tabs of contact, in which these are arranged in the sense of a static tension in the border zone of the conductive segments and, on the other hand, the separation of the contact tabs with respect to the adjacent mounting parts, so that these The latter do not prevent free thermal compensation. In the case of switch according to the invention, in this sense the tabs of contact on its radial inner surfaces are separated with respect to the mounting part arranged contiguously radially inside the contact tabs so that you can vary its distance from the respective mounting part conditioned by thermal expansion. The mentioned separation of the elastic contact tabs with respect to the parts of contiguous remaining switch assembly can comprise, also, especially, a free arrangement of the tabs of contact within corresponding recesses of the body of support, so that the contact tabs starting from your base point and its contact point are surrounded by air; no However, a complete introduction or partial of the elastic contact tabs in a material elastically flexible. By separating the tabs from elastic contact with respect to the adjacent rigid mounting piece radially inside, the contact tabs, depending of the respective thermal expansion of the mounting parts individual, can maintain a greater or lesser radial distance with respect to rigid mounting parts bordering on them radially inside, that is, with respect to the support body formed by molding material. Through the ability to deformation of the contact tabs, in general, tensions acting in the area of the firm union of flush contact tabs with antiparasitic elements, they are reduced so that exclude damages in this union. Thus, the tabs of contact can be specially joined in a lasting way with the antiparasitic elements by means of simple welding joints or also electrically conductive adhesive joints in the area of the contact points.

Thus, by applying the present invention, due to combinations of the characteristic properties for switches according to the invention switches can be manufactured compact, antiparasitic, extremely economical and long life with minimum manufacturing cost.

According to a first preferred variant of switch according to the invention, the antiparasitic elements are made as polygonal multilayer capacitors and arranged along the edges of a square of equal sides around a commutator shaft and, conveniently, in a gap between two conductor segments adjacent to each other. This especially favors simple manufacturing in terms of Procedure and economical of the switch according to the invention.

According to another preferred variant, in the switch according to the invention, the calculated perimeter width of the elastic contact tabs is less than the width of the conductive segments Preferably, also, the length of the contact tabs are in turn greater than the thickness of the contact tabs. This is, on the one hand, advantageous with respect to the elastic flexibility of the contact tabs; in addition to This mode provides favorable mounting behaviors for the antiparasitic elements so that the tabs of contact protrude between the contact poles of two elements antiparasitic contiguous with each other and with the contact poles assigned form a united contact zone, in the sense that bypass the intermediate space between the contact poles of both contiguous antiparasitic elements.

Although the basic concept of this invention can be implemented advantageously in the case of switches of different construction modes (switches of drum, flat switches), in the case of realization of the commutator as drum commutator with a rolling surface cylindrical brush especially highlight the advantages that they can be achieved by the present invention. In the case of said switches according to the invention, which are made as drum switch, according to a particularly preferred variant of the invention, the contact tabs derive from the surface radial inside of the conductive segments. In this way, after the rolling surface of the brush extends in axial direction on the antiparasitic mechanism, a compact mounting mode.

For the conductive union of electricity contact tabs with the antiparasitic elements in the area There are several possibilities of their contact poles. So Especially preferred, the contact tabs are welded to the contact pole of the assigned antiparasitic elements. But, an electrically conductive adhesive bond can also be used advantageously. Under special premises it is even conceivable that a separate bonding material be used as solder or adhesive and get an electrically conductive contact from the tabs of contact with antiparasitic elements only due to a support affected by previous tension of the contact tabs at the contact poles of the antiparasitic elements.

Regarding the realization of the elements of connection, another advantageous variant of the invention is characterized because the connection elements are made as blades of union, which in the case of the realization of the switch are arranged in the area on the front side of the switch opposite the antiparasitic mechanism In this case, the risk of damage from the joints of the contact tabs with the elements antiparasitic during welding the rotor coil to the union blade is minimal.

For a lasting assurance of your position, antiparasitic elements are introduced, especially of preferably, in a support body housing axially inserted into the support body. The walls of limitation of such accommodation, for element support respective antiparasitic in radial sense, in sense perimeter, as well as axially oppose surfaces radial interior and exterior, both front surfaces and to a front surface of the antiparasitic element. The accommodations are limited, especially preferably, radially inside and perimeter in a ring grooved and radially out by molding projections of the support body. The lateral surfaces of the elements antiparasitic are also covered by grooves of the ribbed ring only partially, to facilitate space sufficient for the conductive connection of electricity of the contact tabs to the antiparasitic elements.

The ribbed ring explained above can  extend, especially, in a grooved sleeve, than in the front side of the switch assigned to the deworming mechanism protrudes essentially above the elements antiparasitic, the radial dimensions of the sleeve being fluted equal to or smaller than the radial dimensions of the ring  corrugated. The corresponding ribbed sleeve forms the support for an annular element that serves to record the position Angle of the rotor anchor of magnetized material, which can be composed, especially of ferrite, rare earths or semi -balt. Instead of a ribbed sleeve, the annular element of magnetized material according to another preferred variant of the invention it can also be placed on a centering projection that axial distance from the support body; this allows the fixation of the annular element in the support body in any position of angle of discretion.

The following explains in detail the present invention by means of four preferred embodiments shown in the drawing. It shows:

Fig. 1 an axial section of a first form of realization of a drum switch made according to the present invention,

Fig. 1a an enlarged section of fig. one,

Fig. 2 a section of the drum switch according to fig. 1 along line II-II,

Fig. 2a an enlarged section of fig. 2,

Fig. 3 the enlarged section of an axial section of the drum switch according to fig. 1 and 2 along the line III-III,

Fig. 4 an axial section of a second form of modified embodiment with respect to the embodiment of the fig. 1 to 3 of a drum switch according to the present invention,

Fig. 5 a section of the drum switch according to fig. 4 along the V-V line,

Fig. 6 a cross section of a switch plan made according to the present invention,

Fig. 7 an axial section of the flat switch according to fig. 6 along line VII-VII in the fig. 6,

Fig. 8 an axial section of the flat switch according to fig. 6 and 7 along line VIII-VIII  in fig. 6 and

Fig. 9 an axial section of a modification of the drum switch according to fig. 4 and 5.

The drum switch represented in the Figures 1 to 3 comprise as essential assembly parts a support body 1 made of insulating molding material and ten conductive segments 3 arranged regularly around the switch shaft 2, whose cylindrical contour surfaces define the rolling surface of the brush 4. The body of support 1 has a concentric bore 5 with respect to axis 2, which it is used for the arrangement of the switch on a shovel of the rotor.

The anchor pieces 6 of the segments conductors 3 are introduced into the molding mass of the body of support 1, to anchor the conductive segments also in the case of high torque despite the leakage forces that predominate. On the final side they are provided in the conductive segments 3 connection blades 7, which, in a known way, are used for connection from the coil wires to the switch.

In the environment represented above, the switch according to figure 1 to 3 corresponds to the state of the known technique, so that for your understanding it does not require more explanations

In the area of the front side 8 that opposes the connection blades 7, the switch has a mechanism antiparasitic 9. This comprises ten antiparasitic elements 10 square shaped regularly arranged around the axis of the switch 2 of ceramic material. Also, the elements antiparasitic 10 are arranged in the hollow towards the conductive segments 3. They present, respectively, a function of condenser and dispose, respectively, on two surfaces opposite sides of each other half of metallic layers 11. Each antiparasitic element 10 is housed in a housing 12 in pocket shape of the support body 1. Radially in the interior and perimeter direction the housings 12 are bounded by a perimeter surface 13 or two grooves 14 of a grooved ring 15, which is part of the support body 1; radially out a projection of molding mass 16 of body of support 1 limits the housings 12 for the elements antiparasitic 10. To ensure their position, the elements antiparasitic 10 are stuck in housings 12 assigned.

Near the ends of the segments conductors 3 assigned to the front side 8 of the switch are formed on its inner side 17 radial contact tabs elastic 18. Starting from its respective base point 19, extend the contact tabs 18 in the direction of the front side 8 next to the switch tilted inwards. The contact tabs 18 are not inserted in the molding mass of the support body 1, so that a deformation.

The elastic contact tabs 18 of the conductive segments 3 protrude with their free ends 20 between two antiparasitic elements 10 contiguous with each other. Through a weld joint 21, which in the sense of a contact zone 22 joined comprises both the contact point 23 of the segment conductor 3 arranged at the free end of the tongue of respective contact 18 as well as the contact pole 24 formed by the metallic layers 11 of the antiparasitic elements 10 bordering, each contact tab is permanently attached conducting electricity with both antiparasitic elements contiguous To create enough space for the joints of welding 21, between the grooves 14 of the grooved ring 15 and molding dough projections 16 of support body 1 exist a slack 25.

The embodiment of the switch according to the invention shown in fig. 4 and 5 corresponds to the form of embodiment according to figures 1 to 3 regarding the characteristics of essential configuration. The difference is mainly simply detects that the grooved ring 15 is prolonged in a grooved sleeve 26, which on the front side 8 of the switch assigned to the antiparasitic mechanism 9 protrudes above the antiparasitic elements 10. In the ribbed sleeve 26 places an annular element 27 of magnetized material (for example, ferrite, rare earth semi -balt) and sticks with the sleeve corrugated.

In the case of the piano switch made according to the invention, as shown in fig. 6 to 8, the mechanism antiparasitic 9 'comprising the eight elements antiparasitic 10 is arranged in the area of the front side of the switch opposite to the rolling surfaces of the brush 4. For the antiparasitic mechanism itself the embodiments are useful above for the embodiment according to fig. 1 to 3 of correspondingly, so that to avoid repetitions refers to the description of these drawings. As in the case of drum switch described above, the contact points 23 of the contact tabs 18 are joined by joints of welding 21 with both contiguous antiparasitic elements 10, as represented (only) graphically for one of the contact tabs. The embodiment according to the invention of the antiparasitic mechanism can be performed, in general, in the case of the flat switches regardless of the surface Rolling brush is defined by segments conductors themselves or through segments of material Coal.

The drum switch according to fig. 9 corresponds in terms of its constructive characteristics essential to the drum switch depicted in figures 1 to 3, so that to avoid repetitions it is referred to corresponding embodiments. In turn, the drum switch, as used for the switch according to figures 4 and 5, presented in the front side an annular element 27 of magnetized material. This it is not placed on a ribbed sleeve; but in the case of the drum switch according to fig. 9 the support body 1 is extends to a centering shoulder 28 projecting axially. On it the annular element 27 of magnetized material is placed. By means of an adhesive 30 disposed in the surface area front 29 of the centering shoulder 28, the annular element 27 is firmly connected to the support body 1 of the switch.

Claims (20)

1. Switch for an electric machine, comprising a support body (1) made of insulating molding molding material, a multitude of metal conductor segments (3) arranged thereon regularly around the axis of the switch (2) with elements of connection arranged for a rotor coil and an antiparasitic mechanism (9, 9 '), with which the conductive segments (3) are electrically conductively connected and comprising a number of individual antiparasitic elements (10) corresponding to the number of conductor segments (3), in which the conductor segments (3) have contact tabs (18), which away from their base points (19) are joined at contact points (23) assigned with the contact poles (24) adjacent to two adjacent antiparasitic elements (10), characterized in that the contact tabs (18) are made elastically radially and in the area between their base point (19) and their point or of contact (23) are separated from the adjacent rigid mounting parts of the switch, so that in this area the relative position of the contact tabs (18) with respect to these adjacent rigid mounting parts of the switch can be varied conditioned by thermal expansion 2. Switch according to claim 1, characterized in that the antiparasitic elements (10) are made as multilayer square-shaped capacitors. 3. Switch according to claim 1 or claim 2, characterized in that the contact tabs (18) protrude between the contact poles (24) of two adjacent parasitic elements (10), bridging the contact tabs (18) the space intermediate between the contact poles (24) of the two adjacent antiparasitic elements (10). Switch according to one of claims 1 to 3, characterized in that the antiparasitic elements (10) are arranged at an equal distance along the edges of a polygon of equal sides, around the axis of the switch (2). 5. Switch according to one of claims 1 to 4, characterized in that the width of the elastic contact tongues (18) calculated perimetrically is smaller than the width of the conductive segments (3). Switch according to one of claims 1 to 5, characterized in that the length of the contact tongues (18) is essentially greater than their width and this in turn is greater than the thickness of the contact tongues (18). 7. Switch according to one of claims 1 to 6, characterized in that it is made as a drum switch with a cylindrical brush roller surface (4). 8. Switch according to claim 7, characterized in that the contact tabs (18) derive from the inner radial surface (17) of the conductive segments (3). 9. Switch according to claim 7 or claim 8, characterized in that the rolling surface of the brush (4) extends axially over the antiparasitic mechanism (9) the radial thickness of the conductive segments (3) being below the Rolling surface of the brush (4) even in the area of the antiparasitic mechanism (9), greater than 0.5 mm. 10. Switch according to one of claims 7 to 9, characterized in that the antiparasitic mechanism (9) is arranged on the front side of the switch opposite to the connecting elements for the rotor coil. 11. Switch according to one of claims 1 to 5, characterized in that it is made as a flat switch, in which the antiparasitic mechanism (9 ') is arranged on the front side of the switch assigned to the connection elements for the rotor coil. 12. Switch according to one of claims 1 to 11, characterized in that the contact tabs (18) are welded at the contact poles (24) of the antiparasitic elements (10) assigned or bonded to conduct electricity. 13. Switch according to one of claims 1 to 12, characterized in that the contact tabs (18) are elastically presented for the support of the antiparasitic elements (10) assigned in the contact poles (24). 14. Switch according to one of claims 1 to 13, characterized in that the antiparasitic elements (10) are respectively inserted in a housing (12) of the support body (1), whose limiting walls oppose the radial inner and outer surfaces , to both lateral surfaces and to a front surface of the respective antiparasitic element. 15. Switch according to claim 14, characterized in that the housings (12) are limited radially inside and perimetrically by a grooved ring (15) and radially outside by projections of molding material (16) of the body of support (1). 16. Switch according to claim 15, characterized in that the corrugated ring (15) extends into a corrugated sleeve (26), which protrudes on the front side (8) of the switch assigned to the antiparasitic mechanism (9) above the elements antiparasitic (10), the radial dimensions of the corrugated sleeve (26) being equal to or smaller than the radial dimensions of the corrugated ring (15). 17. Switch according to claim 16, characterized in that an annular element (27) of magnetized material is placed on the corrugated sleeve (26). 18. Switch according to claim 17, characterized in that the annular element (27) is composed of ferrite, rare earths or semi-base. 19. Switch according to claim 17 or claim 18, characterized in that the annular element (27) is glued with the grooved sleeve (26). 20. Switch according to one of claims 1 to 15, characterized in that the support body (1) on its front side (8) assigned to the antiparasitic mechanism (9) is extended in a centering projection, on which an element is placed annular (27) of magnetized material.